This disclosure relates generally to multicast data transmission and, more specifically, to a method and a system for ensuring complete transmission of multicast files with minimum retransmissions.
A computer network generally has at least one computer (a server) that provides services to other computers (clients) via the network. Traditionally, network communications have employed a unicast transmission model in which a separate connection is made between a server and each of its clients. This model works particularly well when each client has unique demands of the server. However, when each client is receiving the same data, multiple copies of the same information packet can flood the network, causing congestion and escalating bandwidth requirements.
Multicasting may alleviate some of the problems associated with unicasting by enabling a server to transmit a single packet of information that may be received by multiple clients who have requested the information. Multicast enabled switches and routers permit the single packet of information to be copied so that only a single packet need be forwarded through each branch of the network to reach the clients requesting the information. Although multicasting may be used in a wide variety of applications in which large amounts of information are being sent to multiple clients, multicasting generally used for applications in which many clients want the identical data simultaneously. Such applications may include live audio or video transmissions, multi-user games, and real-time stock tickers.
Despite the benefits of multicasting for some applications, present implementations of multicasting do not enable a server to receive performance information back from clients, and therefore, transmission reliability may be sacrificed. Current methods of multicasting may also result in unrecoverable data loss.
Therefore, what is needed is an improved method and a system for the complete transmission of multicast files. It is also desirable to maintain efficiency by minimizing retransmissions.